1. Field of the Invention
This invention relates to a multi-position track width sensor for agricultural sprayers and more particularly to a means which enables the sprayer operator to adjust the track width of the vehicle in a precise manner without dismounting the vehicle.
2. Description of the Related Art
High clearance vehicles such as the RoGator® 864 and 1264 manufactured by Ag-Chem, a division of AGCO Corporation, 4205 River Green Parkway, Duluth, Ga. 30096, are used to spray fields with pre-emerge and post-emerge chemicals, fertilizers, insecticides, etc. Other types of high clearance vehicles are described in U.S. Pat. Nos. 6,206,125; 5,282,644; 4,619,340; 5,083,630; and 3,964,565. The RoGator® vehicles, as well as the vehicles of the above-identified patents, include mechanisms to adjust the wheel spacing, track width or tread width of the vehicle to enable the vehicle to be used in different row crop spacings. Many of the prior art vehicles of the type described utilize transversely extending axle mechanisms which are moved inwardly and outwardly with respect to the vehicle chassis to vary the track width. In most cases, the axle assemblies are moved transversely by means of a hydraulic cylinder.
For example, in the RoGator® vehicles, each of the front and rear axle assemblies include a tubular axle housing having a pair of axle members slidably mounted therein with each of the axle members being slidably moved by means of a hydraulic cylinder connected thereto. In the RoGator® vehicles, a yard stick-type of printed or painted scale is provided on each axle member which indicates the amount of extension or retraction of the axle member with respect to the axle housing. The track width of the RoGator® vehicles is adjusted as follows: (1) the vehicle is slowly moved forwardly or rearwardly as the hydraulic cylinder for the first axle member is operated to extend or retract the axle member with respect to its respective tubular axle housing until the operator believes the axle member has been retracted or extended to the desired location; (2) the operator brings the vehicle to a halt; (3) the operator dismounts from the vehicle and reads the track width scale on the axle member being adjusted; (4) if the axle member is not exactly positioned in the desired position, which is the usual case, the operator mounts the vehicle and moves the same forwardly or rearwardly while operating the same hydraulic cylinder again until the operator believes that the axle member is in its desired retracted or extended position; (5) steps (3) and (4) are repeated until the axle member is in the proper position; and (6) steps (1)–(5) are repeated for the other three axle members. In some cases, the operator may attempt to adjust one or more axle members simultaneously rather than sequentially. As can be appreciated, the adjustment of the track width of the vehicle is tedious and time-consuming.